Balloon catheters are well known medical devices in which an inflatable member is located adjacent to the distal end of the catheter shaft and inflated once the catheter is positioned within the body of the patient to anchor the distal end. Such catheters comprise an elongated shaft defining a drainage lumen and an inflation lumen. The drainage lumen comprises a major portion of the cross-section of the catheter shaft and is closed at its distal end by a tip portion. Openings or ports distal to the balloon permit fluid to enter the drainage lumen. The proximal end of the drainage lumen is placed in fluid communication with a method of drainage such as a urinary drainage bag. In some embodiments, the communication is made through a drainage funnel located at the proximal end of the catheter through which the drainage lumen opens.
The inflation lumen is formed within the wall of the catheter shaft and extends from a location inside of the balloon, along the catheter shaft, and through an opening, typically a branch adjacent the proximal end of the shaft. An inflation valve at the end of the branch or other opening permits fluid to be infused into the inflation lumen.
For urinary catheters such as Foley catheters, the catheter is introduced into the patient and is advanced into the urethra and advanced until the distal end of the catheter, including the balloon, resides within the bladder. The balloon is then inflated, typically by coupling a syringe to the inflation valve and actuating it to discharge fluid from the syringe, through the inflation lumen, and into the balloon.
To remove a balloon catheter, it is first necessary to deflate the balloon anchoring the distal end of the catheter. This is done by withdrawing fluid through the inflation lumen, typically through a syringe coupled to inflation lumen through an inflation valve. On occasion, it proves difficult or impossible to deflate the balloon in the normal manner. When this happens, it becomes necessary to take extraordinary means such as inserting an instrument up the catheter through the inflation lumen or through the bladder to pierce the balloon to allow the inflation medium to escape. Addition of mineral oil can also be used to cause the balloon to weaken and rupture. These procedures may cause the patient additional discomfort and may lead to adverse clinical consequences.
Thus there is a need for a balloon catheter with improved resistance to non-deflation.